Cisco Unified Communications Solutions unify voice, video, data, and
mobile applications on fixed and mobile networks. This enables easy
collaboration every time from any workspace. Cisco IP Communicator brings your
phone to your PC. This allows you to make calls with your corporate phone
number no matter where you are working.

The information in this document is based on these software and
hardware versions:

Cisco IP Communicator 8.6

Cisco Unified Communications Manager (CUCM) 8.x

The information in this document was created from the devices in a
specific lab environment. All of the devices used in this document started with
a cleared (default) configuration. If your network is live, make sure that you
understand the potential impact of any command.

Cisco IP Communicator is a Microsoft® Windows-based soft-phone
application that brings your work telephone to your personal computer. It is
easy to deploy, and includes some of the latest technology and advancements
available for IP communications. This advantage boosts business collaboration
and responsiveness, and helps organizations keep pace with the current mobile
business environment.

Directories: Cisco IP Communicator identifies incoming calls and
messages, and categorizes them on the screen. This allows you to return calls
quickly and effectively using direct dial-back capability. The corporate
directory integrates with the Lightweight Directory Access Protocol Version 3
(LDAPv3) standard directory.

Settings: This key allows you to select from a large number of ringer
sounds and background images.

Services: Cisco IP Communicator allows you to quickly access diverse
information such as weather, stocks, quote of the day, or any other web-based
information. The phone uses XML to provide a portal to an ever-growing world of
features and information.

Help: The online Help feature gives you information about the phone
keys, buttons, and features.

ASA intercepts and authenticates Cisco IP Communicator traffic before
it reaches Communications Manager by forcing all soft client media to proxy via
the ASA appliance. This ensures a single, secure point of entry to the voice
VLAN.

Cisco IP Communicator supports the same call control and application
protocols as the 7970s. At startup, the Cisco IP Communicator interacts with
the network as follows:

Locate the configuration server: After startup, Cisco IP Communicator
always attempts to use DHCP to locate its TFTP server. Similar to other phones,
Cisco IP Communicator can use TFTP to retrieve files from the server. It can
also use HTTP to retrieve software updates, thereby accelerating file transfer
for remote users.

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Request the CTL file (if security is configured): The TFTP server
stores the CTL file, which contains a list of Cisco Unified CallManagers and
TFTP servers that Cisco IP Communicator is authorized to connect to. It also
contains the certificates necessary for establishing a secure connection
between Cisco IP Communicator and Cisco Unified CallManager. The security
CTLFile.tlv file is downloaded to the Program Files
> Cisco Systems > Cisco IP Communicator > AppData > sec
folder.

Request configuration files: Configuration files (.cnf.xml) reside on
the TFTP server and define parameters for connecting to Cisco Unified
CallManager. In general, any time you make a change in Cisco Unified
CallManager that requires a device to be reset, a change is made to the
configuration file for that device. If you have enabled auto-registration in
Cisco Unified CallManager, Cisco IP Communicator accesses a default
configuration file (xmldefault.cnf.xml) from the TFTP server. Otherwise, Cisco
IP Communicator accesses a .cnf.xml file corresponding to its device
name.

Update software: If you use AutoUpdate, the .cnf.xml file contains
the information that tells Cisco IP Communicator which software version it
should run. If this software version differs from the one currently in use,
Cisco IP Communicator contacts the TFTP server to request the new software
file. In order to make this request, Cisco IP Communicator first tries to use
HTTP. If you have not enabled HTTP access, Cisco IP Communicator uses
TFTP.

Contact Cisco Unified CallManager: After obtaining the configuration
file from the TFTP server, Cisco IP Communicator attempts to make a connection
to the highest priority Cisco Unified CallManager on the list. If security is
implemented, Cisco IP Communicator makes a TLS connection. Otherwise, it makes
a non-secure TCP connection. If the device was added to the database
individually (through Cisco Unified CallManager Administration or in bulk
through the Bulk Administration Tool (BAT), Cisco Unified CallManager
identifies the device. This is only true if you are not using BAT with the Tool
for Auto-Registered Phones Support (TAPS). Otherwise, the device attempts to
register itself in the Cisco Unified CallManager database (when
auto-registration is enabled in Cisco Unified CallManager).

Note: Auto-registration is disabled when security is enabled on CUCM. In
this case, you must manually add Cisco IP Communicator to the Cisco Unified
CallManager database.